Control apparatus for internal combustion engine and control method for internal combustion engine

Abstract

A control apparatus for an internal combustion engine includes an electronic control unit that is configured to perform an operation of making a lift amount of a specific valve corresponding to one of either intake ports or exhaust ports for a specific cylinder in which an amount of condensate water produced in the port or flowing into the port is larger than in the other cylinders when the engine is stopped, in a case where production of condensate water in the ports or inflow of condensate water into the ports is predicted.

What is claimed is: 
     
       1. A control apparatus for an internal combustion engine, the internal combustion engine including a plurality of cylinders and ports, the ports including intake ports and exhaust ports corresponding to the plurality of the cylinders respectively, and the internal combustion engine being an internal combustion engine in which amounts of condensate water produced in the ports or flowing into the ports are different from one another among the cylinders due to differences in shape or arrangement of the ports or conduits leading to the ports among the plurality of the cylinders as to either the intake ports or the exhaust ports,
 the control apparatus comprising 
 an electronic control unit configured to perform an operation of making a lift amount of a specific valve corresponding to one of either the intake ports or the exhaust ports equal to zero for a specific cylinder when the internal combustion engine is stopped, in a case where the electronic control unit predicts that condensate water is produced in one of either the intake ports or the exhaust ports or condensate water flows into one of either the intake ports or the exhaust ports, and the specific cylinder being a cylinder in which an amount of condensate water produced in one of either the corresponding intake ports or the corresponding exhaust ports or condensate water flowing into one of either the corresponding intake ports or the corresponding exhaust ports is larger than in the other ones of the plurality of the cylinders. 
 
     
     
       2. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the internal combustion engine includes an exhaust gas recirculation device that recirculates part of exhaust gas to an intake passage, 
 the ports in which condensate water is produced or into which condensate water flows are the intake ports, and 
 the specific valve is an intake valve. 
 
     
     
       3. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the internal combustion engine includes a compressor and an intercooler in the intake passage, 
 the ports in which condensate water is produced or into which condensate water flows are the intake ports, and 
 the specific valve is the intake valve. 
 
     
     
       4. The control apparatus for the internal combustion engine according to  claim 3 , wherein the specific cylinder is a cylinder in which an intake path from the intercooler to the intake valve is shorter than in the other cylinders. 
     
     
       5. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the specific cylinder is a cylinder in which an intake path from a surge tank to an intake valve is shorter in the other cylinders, and 
 the specific valve is the intake valve. 
 
     
     
       6. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the internal combustion engine is a V-engine that is mounted on a vehicle while being inclined in a rotational direction of a crankshaft, and 
 the specific cylinder is a cylinder that is provided in that one of two banks constituting the V-engine in which an angle formed by a direction of connection of one of either the intake ports and the exhaust ports to a combustion chamber and a vertical direction is smaller than in the other bank. 
 
     
     
       7. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the electronic control unit is configured to estimate amounts of condensate water in either the intake ports or the exhaust ports individually for the cylinders when the engine is stopped, and 
 the electronic control unit is configured to determine the specific cylinder based on amounts of condensate water in the respective cylinders. 
 
     
     
       8. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the electronic control unit is configured to estimate an amount of condensate water in the entire internal combustion engine as to the either the intake ports or the exhaust ports, 
 the electronic control unit is configured to perform the operation of making a lift amount of the specific valve equal to zero when the internal combustion engine is stopped, in a case where the estimated amount of condensate water is larger than a predetermined threshold, and 
 the electronic control unit is configured not to perform the operation of making the lift amount of the specific valve equal to zero when the internal combustion engine is stopped, in a case where the estimated amount of condensate water is equal to or smaller than the threshold. 
 
     
     
       9. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the electronic control unit is configured to perform the operation of making the lift amount of the specific valve equal to zero when the internal combustion engine is stopped, after a rotational speed of the internal combustion engine becomes equal to or lower than a predetermined rotational speed. 
 
     
     
       10. The control apparatus for the internal combustion engine according to  claim 1 , wherein
 the electronic control unit is configured to control a stop crank angle of the internal combustion engine such that one of the cylinders other than the specific cylinder first enters a suction stroke in starting the engine next time, when the specific valve is the intake valve and the operation of making the lift amount of the specific valve equal to zero is performed when the internal combustion engine is stopped. 
 
     
     
       11. A control method for an internal combustion engine, the internal combustion engine including a plurality of cylinders and ports, the ports including intake ports and exhaust ports corresponding to the plurality of the cylinders respectively, and the internal combustion engine being an internal combustion engine in which amounts of condensate water produced in the ports or flowing into the ports are different from one another among the cylinders due to differences in shape or arrangement of the ports or conduits leading to the ports among the plurality of the cylinders as to either the intake ports or the exhaust ports,
 the control method comprising: 
 performing, by an electronic control unit, an operation of making a lift amount of a specific valve corresponding to one of either the intake ports or the exhaust ports for a specific cylinder when the internal combustion engine is stopped, in a case where the electronic control unit predicts that condensate water is produced in one of either the intake ports or the exhaust ports or condensate water flows into one of either the intake ports or the exhaust ports, and the specific cylinder being a cylinder in which an amount of condensate water produced in one of either the corresponding intake ports or the corresponding exhaust ports or condensate water flowing into one of either the corresponding intake ports or the corresponding exhaust ports is larger than in the other ones of the plurality of the cylinders.